Joint warfare in South Vietnam, 1963–69
In the Vietnam War, after the assassinations of Ngo Dinh Diem and John F. Kennedy in late 1963 and the Gulf of Tonkin incident in 1964 and the continuing political instability in the South, the United States made a policy commitment to begin joint warfare in South Vietnam, a period of gradual escalation and Americanization, involving the commitment of large-scale combat forces from the United States and allied countries. It was no longer assumed the Republic of Vietnam could create a desirable situation without major external assistance. This phase of the war lasted until the election of Richard Nixon, and the change of U.S. policy to Vietnamization, or giving the main combat role back to the South Vietnamese military.The North Vietnamese term for the large-scale introduction of U.S. ground forces, in 1965, is the Local War, according to Gen. Trần Văn Trà, the [North Vietnamese] "" Party concluded, the ""United States was forced to introduce its own troops because it was losing the war. It had lost the political game in Vietnam....the situation allows us to shift our revolution to a new stage, that of decisive victory."" The Party issued a resolution to this effect, which was transmitted, in October 1967, to the Central Office for South Vietnam and to key officials of the major commands in the South. They were directed to begin detailed planning for what was to become the Tet Offensive. Note that there was a delay of approximately two years between the Politburo decision and the directive to begin planning, so it can be asked if the Politburo did actually make the broad strategic decision in 1965, or some time later, as they grew more aware of the effect of U.S. operations.Robert McNamara suggests that the overthrow of Dương Văn Minh by Nguyễn Khánh, in January 1964, reflected different U.S. and Vietnamese priorities. ""And since we still did not recognize the North Vietnamese and Vietcong and North Vietnamese as nationalist in nature, we never realized that encouraging public identification between Khanh and America may have only reinforced in the minds of many Vietnamese that his government drew its support not from the people, but from the United States.""